From 9e3f1d0805b2d919904dd9a4ff0d956314cc3cba Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@nbd.name>
Date: Sat, 8 Jul 2017 08:20:09 +0200
Subject: debloat: procfs

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 fs/locks.c               |  2 ++
 fs/proc/Kconfig          |  5 +++++
 fs/proc/consoles.c       |  3 +++
 fs/proc/proc_tty.c       | 11 ++++++++++-
 include/net/snmp.h       | 18 +++++++++++++++++-
 ipc/msg.c                |  3 +++
 ipc/sem.c                |  2 ++
 ipc/shm.c                |  2 ++
 ipc/util.c               |  3 +++
 kernel/exec_domain.c     |  2 ++
 kernel/irq/proc.c        |  9 +++++++++
 kernel/time/timer_list.c |  2 ++
 mm/vmalloc.c             |  2 ++
 mm/vmstat.c              |  8 +++++---
 net/8021q/vlanproc.c     |  6 ++++++
 net/core/net-procfs.c    | 18 ++++++++++++------
 net/core/sock.c          |  2 ++
 net/ipv4/fib_trie.c      | 18 ++++++++++++------
 net/ipv4/proc.c          |  3 +++
 net/ipv4/route.c         |  3 +++
 20 files changed, 105 insertions(+), 17 deletions(-)

--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2812,6 +2812,8 @@ static const struct file_operations proc
 
 static int __init proc_locks_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
 	proc_create("locks", 0, NULL, &proc_locks_operations);
 	return 0;
 }
--- a/fs/proc/Kconfig
+++ b/fs/proc/Kconfig
@@ -81,3 +81,8 @@ config PROC_CHILDREN
 
 	  Say Y if you are running any user-space software which takes benefit from
 	  this interface. For example, rkt is such a piece of software.
+
+config PROC_STRIPPED
+	default n
+	depends on EXPERT
+	bool "Strip non-essential /proc functionality to reduce code size"
--- a/fs/proc/consoles.c
+++ b/fs/proc/consoles.c
@@ -106,6 +106,9 @@ static const struct file_operations proc
 
 static int __init proc_consoles_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
+
 	proc_create("consoles", 0, NULL, &proc_consoles_operations);
 	return 0;
 }
--- a/fs/proc/proc_tty.c
+++ b/fs/proc/proc_tty.c
@@ -145,7 +145,10 @@ static const struct file_operations proc
 void proc_tty_register_driver(struct tty_driver *driver)
 {
 	struct proc_dir_entry *ent;
-		
+
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
+
 	if (!driver->driver_name || driver->proc_entry ||
 	    !driver->ops->proc_fops)
 		return;
@@ -162,6 +165,9 @@ void proc_tty_unregister_driver(struct t
 {
 	struct proc_dir_entry *ent;
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
+
 	ent = driver->proc_entry;
 	if (!ent)
 		return;
@@ -176,6 +182,9 @@ void proc_tty_unregister_driver(struct t
  */
 void __init proc_tty_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
+
 	if (!proc_mkdir("tty", NULL))
 		return;
 	proc_mkdir("tty/ldisc", NULL);	/* Preserved: it's userspace visible */
--- a/include/net/snmp.h
+++ b/include/net/snmp.h
@@ -123,6 +123,21 @@ struct linux_xfrm_mib {
 #define DECLARE_SNMP_STAT(type, name)	\
 	extern __typeof__(type) __percpu *name
 
+#ifdef CONFIG_PROC_STRIPPED
+#define __SNMP_STATS_DUMMY(mib)	\
+	do { (void) mib->mibs[0]; } while(0)
+
+#define __SNMP_INC_STATS(mib, field) __SNMP_STATS_DUMMY(mib)
+#define SNMP_INC_STATS_ATOMIC_LONG(mib, field) __SNMP_STATS_DUMMY(mib)
+#define SNMP_INC_STATS(mib, field) __SNMP_STATS_DUMMY(mib)
+#define SNMP_DEC_STATS(mib, field) __SNMP_STATS_DUMMY(mib)
+#define __SNMP_ADD_STATS(mib, field, addend) __SNMP_STATS_DUMMY(mib)
+#define SNMP_ADD_STATS(mib, field, addend) __SNMP_STATS_DUMMY(mib)
+#define SNMP_UPD_PO_STATS(mib, basefield, addend) __SNMP_STATS_DUMMY(mib)
+#define __SNMP_UPD_PO_STATS(mib, basefield, addend) __SNMP_STATS_DUMMY(mib)
+
+#else
+
 #define __SNMP_INC_STATS(mib, field)	\
 			__this_cpu_inc(mib->mibs[field])
 
@@ -153,8 +168,9 @@ struct linux_xfrm_mib {
 		__this_cpu_add(ptr[basefield##OCTETS], addend);	\
 	} while (0)
 
+#endif
 
-#if BITS_PER_LONG==32
+#if (BITS_PER_LONG==32) && !defined(CONFIG_PROC_STRIPPED)
 
 #define __SNMP_ADD_STATS64(mib, field, addend) 				\
 	do {								\
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -1208,6 +1208,9 @@ int __init msg_init(void)
 {
 	const int err = msg_init_ns(&init_ipc_ns);
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return err;
+
 	ipc_init_proc_interface("sysvipc/msg",
 				"       key      msqid perms      cbytes       qnum lspid lrpid   uid   gid  cuid  cgid      stime      rtime      ctime\n",
 				IPC_MSG_IDS, sysvipc_msg_proc_show);
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -207,6 +207,8 @@ int __init sem_init(void)
 {
 	const int err = sem_init_ns(&init_ipc_ns);
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return err;
 	ipc_init_proc_interface("sysvipc/sem",
 				"       key      semid perms      nsems   uid   gid  cuid  cgid      otime      ctime\n",
 				IPC_SEM_IDS, sysvipc_sem_proc_show);
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -122,6 +122,8 @@ pure_initcall(ipc_ns_init);
 
 void __init shm_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
 	ipc_init_proc_interface("sysvipc/shm",
 #if BITS_PER_LONG <= 32
 				"       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -141,6 +141,9 @@ void __init ipc_init_proc_interface(cons
 	struct proc_dir_entry *pde;
 	struct ipc_proc_iface *iface;
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
+
 	iface = kmalloc(sizeof(*iface), GFP_KERNEL);
 	if (!iface)
 		return;
--- a/kernel/exec_domain.c
+++ b/kernel/exec_domain.c
@@ -42,6 +42,8 @@ static const struct file_operations exec
 
 static int __init proc_execdomains_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
 	proc_create("execdomains", 0, NULL, &execdomains_proc_fops);
 	return 0;
 }
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -396,6 +396,9 @@ void register_irq_proc(unsigned int irq,
 	void __maybe_unused *irqp = (void *)(unsigned long) irq;
 	char name [MAX_NAMELEN];
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED) && !IS_ENABLED(CONFIG_SMP))
+		return;
+
 	if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
 		return;
 
@@ -449,6 +452,9 @@ void unregister_irq_proc(unsigned int ir
 {
 	char name [MAX_NAMELEN];
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED) && !IS_ENABLED(CONFIG_SMP))
+		return;
+
 	if (!root_irq_dir || !desc->dir)
 		return;
 #ifdef CONFIG_SMP
@@ -487,6 +493,9 @@ void init_irq_proc(void)
 	unsigned int irq;
 	struct irq_desc *desc;
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED) && !IS_ENABLED(CONFIG_SMP))
+		return;
+
 	/* create /proc/irq */
 	root_irq_dir = proc_mkdir("irq", NULL);
 	if (!root_irq_dir)
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -389,6 +389,8 @@ static int __init init_timer_list_procfs
 {
 	struct proc_dir_entry *pe;
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
 	pe = proc_create("timer_list", 0444, NULL, &timer_list_fops);
 	if (!pe)
 		return -ENOMEM;
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2770,6 +2770,8 @@ static const struct file_operations proc
 
 static int __init proc_vmalloc_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
 	proc_create("vmallocinfo", S_IRUSR, NULL, &proc_vmalloc_operations);
 	return 0;
 }
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1951,10 +1951,12 @@ void __init init_mm_internals(void)
 	start_shepherd_timer();
 #endif
 #ifdef CONFIG_PROC_FS
-	proc_create("buddyinfo", 0444, NULL, &buddyinfo_file_operations);
-	proc_create("pagetypeinfo", 0444, NULL, &pagetypeinfo_file_operations);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED)) {
+		proc_create("buddyinfo", 0444, NULL, &buddyinfo_file_operations);
+		proc_create("pagetypeinfo", 0444, NULL, &pagetypeinfo_file_operations);
+		proc_create("zoneinfo", 0444, NULL, &zoneinfo_file_operations);
+	}
 	proc_create("vmstat", 0444, NULL, &vmstat_file_operations);
-	proc_create("zoneinfo", 0444, NULL, &zoneinfo_file_operations);
 #endif
 }
 
--- a/net/8021q/vlanproc.c
+++ b/net/8021q/vlanproc.c
@@ -127,6 +127,9 @@ void vlan_proc_cleanup(struct net *net)
 {
 	struct vlan_net *vn = net_generic(net, vlan_net_id);
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return;
+
 	if (vn->proc_vlan_conf)
 		remove_proc_entry(name_conf, vn->proc_vlan_dir);
 
@@ -146,6 +149,9 @@ int __net_init vlan_proc_init(struct net
 {
 	struct vlan_net *vn = net_generic(net, vlan_net_id);
 
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
+
 	vn->proc_vlan_dir = proc_net_mkdir(net, name_root, net->proc_net);
 	if (!vn->proc_vlan_dir)
 		goto err;
--- a/net/core/net-procfs.c
+++ b/net/core/net-procfs.c
@@ -320,10 +320,12 @@ static int __net_init dev_proc_net_init(
 
 	if (!proc_create("dev", S_IRUGO, net->proc_net, &dev_seq_fops))
 		goto out;
-	if (!proc_create("softnet_stat", S_IRUGO, net->proc_net,
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED) &&
+		!proc_create("softnet_stat", S_IRUGO, net->proc_net,
 			 &softnet_seq_fops))
 		goto out_dev;
-	if (!proc_create("ptype", S_IRUGO, net->proc_net, &ptype_seq_fops))
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED) &&
+		!proc_create("ptype", S_IRUGO, net->proc_net, &ptype_seq_fops))
 		goto out_softnet;
 
 	if (wext_proc_init(net))
@@ -332,9 +334,11 @@ static int __net_init dev_proc_net_init(
 out:
 	return rc;
 out_ptype:
-	remove_proc_entry("ptype", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED))
+		remove_proc_entry("ptype", net->proc_net);
 out_softnet:
-	remove_proc_entry("softnet_stat", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED))
+		remove_proc_entry("softnet_stat", net->proc_net);
 out_dev:
 	remove_proc_entry("dev", net->proc_net);
 	goto out;
@@ -344,8 +348,10 @@ static void __net_exit dev_proc_net_exit
 {
 	wext_proc_exit(net);
 
-	remove_proc_entry("ptype", net->proc_net);
-	remove_proc_entry("softnet_stat", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED)) {
+		remove_proc_entry("ptype", net->proc_net);
+		remove_proc_entry("softnet_stat", net->proc_net);
+	}
 	remove_proc_entry("dev", net->proc_net);
 }
 
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3378,6 +3378,8 @@ static __net_initdata struct pernet_oper
 
 static int __init proto_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
 	return register_pernet_subsys(&proto_net_ops);
 }
 
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -2731,10 +2731,12 @@ static const struct file_operations fib_
 
 int __net_init fib_proc_init(struct net *net)
 {
-	if (!proc_create("fib_trie", S_IRUGO, net->proc_net, &fib_trie_fops))
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED) &&
+		!proc_create("fib_trie", S_IRUGO, net->proc_net, &fib_trie_fops))
 		goto out1;
 
-	if (!proc_create("fib_triestat", S_IRUGO, net->proc_net,
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED) &&
+		!proc_create("fib_triestat", S_IRUGO, net->proc_net,
 			 &fib_triestat_fops))
 		goto out2;
 
@@ -2744,17 +2746,21 @@ int __net_init fib_proc_init(struct net
 	return 0;
 
 out3:
-	remove_proc_entry("fib_triestat", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED))
+		remove_proc_entry("fib_triestat", net->proc_net);
 out2:
-	remove_proc_entry("fib_trie", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED))
+		remove_proc_entry("fib_trie", net->proc_net);
 out1:
 	return -ENOMEM;
 }
 
 void __net_exit fib_proc_exit(struct net *net)
 {
-	remove_proc_entry("fib_trie", net->proc_net);
-	remove_proc_entry("fib_triestat", net->proc_net);
+	if (!IS_ENABLED(CONFIG_PROC_STRIPPED)) {
+		remove_proc_entry("fib_trie", net->proc_net);
+		remove_proc_entry("fib_triestat", net->proc_net);
+	}
 	remove_proc_entry("route", net->proc_net);
 }
 
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -558,6 +558,9 @@ static __net_initdata struct pernet_oper
 
 int __init ip_misc_proc_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
+
 	return register_pernet_subsys(&ip_proc_ops);
 }
 
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -427,6 +427,9 @@ static struct pernet_operations ip_rt_pr
 
 static int __init ip_rt_proc_init(void)
 {
+	if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+		return 0;
+
 	return register_pernet_subsys(&ip_rt_proc_ops);
 }
 
